Multilayer reversal color film and a method of processing the same



MULTILAYERA REVERSAL COLORFILM AND METHOD OF PROCESSING THE SAME' Filed NOV. 6, 1942 IN V EN TORS Herman /z/err Patented im. is, i946 MUL'rmrna aEvEasAL coma FILM AND A Mn'rnon or raocsssme 'ma sama Herman n. num and Herbert w. Marteau, sr., Binghamton, N. Y., assignors to General Aniline & Film Corporation, New -York, N. Y., a corporation of Delaware Application November 6, 1942, Serial No. @1315 three sensitive layers must produce satisfactory 9 illlaims.l

The present inventionrelates to multilayer reversal colorlmhaving a high speed and iine grain, amenable to control of the color balance and to a method of processing the same.

Multilayer colorlm is known in which the three layers sensitive respectivelyV to red, green and blue light, contain color formers which are take care of irregularities which may be inherent i fast to diffusion. A, method of processing such iilm by the reversal method involving the forma,

tion of dye images by reaction of the color formers in the emulsion layers with the oxidation products of an aromatic amino developer, is-also known,` as may be appreciated fromv a reference to U. S. P. 2,179,234. While such iiim and the processing of the same bythe method of said patent leads generally to satisfactory results, the illm'ls not entirely free from objections.

The cyan image is the key image in subtractiveM color photography and it is therefore essential that the layer destined to contain such image be amenable to processing to produce a 'strong' image.` This inturn means that the iilm must dye images inthe single developing step, and precludes a, possibility of adjusting the reaction to particularly in the red-sensitive layer. inasmuch as it is dimcult to obtain an absolute uniformity in all of the layers so that the reaction producing 'the dye image leads to images having a proper color balance, a further problem is presented by the fact thatwhere the color formers are located in the iilm itself, compensation for irregularities cannot be effected by adjusting the time of development.

We have now found that wide latitude in the4 selection oi color farmers and sensitizers can be insured with the production of a lm giving the desired color balance by producing a film in which the color formera for the yellow and magenta limages are located in the blueand green-sensihave a satisfactorily high speed. In order to obtain the desired speed, resorty must be had tothe usual powerful redsensitizers. It is a peculiarity of the color formers utilized to produce cyan dye images that for the most part they have-a tendency to displace the sensitizers from the silver halide grains. Since the ability of a sensitizer to adequately perform its function depends upon its absorption by the silver halide grains, a displacement of the sensitizers from the grains by the color farmers leads to emulsion layers of low speed. While some of the red sensitizers are compatible with cyan color farmers, and may sensitize properly when present in the layer with cyan color formers, nevertheless the number of such sensitizers is relatively restricted. l

There are many color formers capable of producing dye images upon` reaction with the oxidation products of aromatic primary lamino developera. However, the number of color farmers which are capable of permitting the introduction of groups rendering the color formers fast to diffusion without detrimentally influencing the speed or color absorption of the resulting dyes, is relatiyely small. Therefore there is a definite limitation placed upon the art, mst as regards f colorformers when utilizing film to be produced according to U. S. P., 2,179,234, and second as regards sensitizers. l

This limitation in .thefselection of the sensi- Vtive layers, respectively, whereas no color former is located in the red-sensitive layer, and separately processing the red-sensitive layer so as to permit an' adjustment of the time of development.

The production of such illm and the processing of they same constitute the purposes and objectsY of the present invention.

The invention will be more readily understood by reference to the accompanying drawing which discloses in section a nlm of the type contemplated herein. Figure 1 of the drawing discloses one modication, and Figure 2 a diiierent modification. A

Referring to Figure l, reference numeral l discloses an antihaiation layer removable in an alkaline solution or decolorizable in the developing process. A suitawble antihalation layer in the first category consists of an alkali-soluble resin such as is described in U. S. P. 2,161,788 and contain# ing dyessuch as are mentioned in U. S. P. 2,147,112. An antihalationlayer falling within the second category is a colloidal` silver layer ,'such as that described in U. S. P. 2,220,187. ,6

- represents a nlm base on which are supported ve superimposed layers` three layers of which are 'gelatina-silver halide emulsion layers. Layer 5 is a red-sensitive silver halide llayer which contains no color component. Due to the absence of the color component, ne may use any of the tizers and the color formers it.' not the only problem which confronts the art when working according to said patented procedure. In the patented procedure, all ci the dye imagesare promown powerful sensitizers for red without any fear of a detrimentalaction on'the sensitizeig. Layer 3 is a green-sensitive silver halide emulsion .layer vcontaining a non-diffusing magenta color component. Satisfactory color components for the magenta image are'the non-diusing components described inv U. SQPatents 2,178,612 and 2,179,238. Examples of auch components are the condensation products of meta-amino-phenylmethyl-pyrasolone, and the mixed polymer o;

vinyl chloride and maleic acid anhydride, paramethyl--pyrazolone and the like. Layer l is a blue-sensitive silver halide emulsion layer containing a non-diiiusing yellow color component:

of such components are terephthaloyl-bis-acetic acid ani1idp'carboxylic acid and the like. interposed between the blue-sensitive layer I and the green-sensitive layer 3 is a yellow lter layer which may be ot colloidal silver or which may be of a yellow dyestuif of the type contemplated in U. S. P. 2,187,731. Interposed between the greensensitive layer 3 andi the red-sensitive layer! is a third gelatin layer which may, however, lbe omitted without any particular sacrifice of resuits.

The multilayer film may be processed by exposing the same to a colored object and developing the film to a negative in a developer which will not couple with the Acomponents in the blueand green-sensitive layers. For this purpose one may utilize the amidol developer described in U. S. P. 2,179,234. The red-sensitive bottom layer is then exposed throughthe base to red light without affecting the green-sensitive and bluesensitive layers. The re-exposed red-sensitive layer is then color-developedQin a developer containing a cyan colr component which oi course must be one which is diffusing rather than nondiifusing. Suitable cyan developers 'are those mentioned in U. S. P. 2,191,502 and 1,969,452.

. Examples of such developers are:

Sodium vsulte (anh.) g-- Potassium carbonate g Diethyl D phenylenediamine hydrochloride e 3 Water l 1 2.3.4-trichlor-alpha naphthol 2 Dissolved in ethyl alcohol cc 25 or y Sodium sulflte g-- 40 Sodium carbonate .g-- 60 Diethyl p phenylenediamine hydrochliride g-- 3 2.4 dichloro a-naphthol g-- 2 In acetone cc-- 60 Water to make l-- 4 In lieu of the naphthols mentioned in the above formulae, one may employ a-naphthol and pentabrom-a-naphthol or meta-hydroxydiphenyl. Following the formation of the cyan color image, the blue-sensitive top layer and green-sensitive middle layers are simultaneously exposed to bluegreen light and developed in a color-.forming developer which is free from color-forming substances. Developers of this type are paraphenylenediamine developers, and we have found that, satisfactory results may be obtained when using the developer mentioned in U. S. P. 2,179,234. By this step a yellow image is formed in the blues sensitive top layer and al magenta image in the green-sensitive middle layer. The multilayer tllm is now subjected anide' bleaching bath t0`eifect a removalv of both the positive and negative silver, after which itis ilxed, washed and dried. Suitable silver-bleaching baths are those referred to in U. S. P. 2,113,329. Examples of silver bleaching baths-,which we have found to be particularly effective are the followto bleaching in a ferricy' -aseaoev Potassium ferrlcyanlde gms Water to--- or' 1000 or l Cupric chloride gms-- 20 Potassium bromidegms '10 Water to cc-; 1000 Ammonium bromide gms 75 Iodine (cryst.) gms-- 3 Water to cc 1000 A xing bath; ofA 10% sodium thiosulilte may be used. The film is now ready for projection.

It will be appreciated that since color is introduced into the red-sensitive bottom layer by a separate development step, and since the silver halide which is responsible for color formation is exposed by a separate step, itis possible to control the color balance by adjusting the re-exposure and developing time of the red-sensitive layer. The advantages of this processing over the processing disclosed in U. S. P. 2,179,234 will become immediately apparent.

It is of course not essential that one adhere strictly to the sequence of steps which have been just related. Thus, we have worked up the 'film by jre-exposing the two top layers with blueycyan color component. ging agents are those disclosed in U. S. P.

green light following the black-'and-white development and have then developed these in a color-forming developerv free 'from color components, such as that mentioned above. After this, the cyan layer may be exposed and processed as previously described. Furthermore, it is not necessary to employ light for re-exposure of the various layers. Thus in either of the procedures outlined, the two top layers may be simultaneously fogged by exposure with minus red, light and then color developed while the red-sensitive bottom layer' may be chemically fogged and then color developed lwith a 'developer containing a Suitable chemical fog- 2,159,466. An example of a fogging agent which we have found to give particularly goodvresults is:

'waz-.er cc 1o`oo Glacial acetic acid-; cc 5 Thiosinamine gr-- 0.4

l,One may utilize, in place of the thiosinamne in this example, n-phenyl thiourea, N-N diethyl-N'- allyl thiourea,- N-N diethano-N'phenylthlourea and the like. f'

It-will be observed from a reference toFigure 2 that the film thereof is similar to that of Figure -forming components mentioned for use in the `blue and green-sensitive emulsion layers `of Figure l1 may likewise be used in the film of Figure 2.

The illm of this ilgure is processed'by exposing it to a colored object and developing it to a blackand-white negativein a developer such as amidol,

the oxidation products' of which do not couple with the color components in the blueand greensensitive layers. 'i'hebottom layer then 'exexposure of the magenta, layer is prevented. The

red-sensitive layer is then developed in a color developer containing a cyan color-coupling component oi the type described above. Here, again, color balance can be assured by correlating the time of exposure with the time of development. 'I'he blue-sensitive top layer and the green-sensitive intermediate layer ,are now exposed with white light and developed in a color-forming developer free from color-forming sutances. The developer mentioned above may also be employecl in this instance. Finally, the illm is bleached with a silver bleaching bath of the type recommended above and after xlng is Washed and dried. The iilm is then ready for projection and it will be found to have a proper color balance.

It will be seen that working by the method claimed, any red sensitizer suitable for the sensi- 1 tizing of a silver halide emulsion to the red region of the spectrum may he utilized, inasmuch as no color formers are present in the red-sensitive layer and hence one may disregard the fact that cyan color formers normally have a greater ailinity for silver halide grains than do red sensitizers. Similarly, by utilizing a diiusing color component for production of the. cyan image, the number of possible color formers which the art may select is greatly enhanced, since one need not pay any particular attention to the necessity pf incorporating groups into the color former which would render the same fast to diffusion. Finally, by permitting a separate development of the redsensitive layer, the time of development may be so correlated with the other factors as to insure a proper color balance between the various dye nnages.

YModiilcations of the invention will occur to persons skilled in the art and We therefore do not intend to be limited in the patent granted, except as required by the claims and the prior art.

We claim:

1. The method of producing multicolor photographs which comprises -exposing a multilayer 111m comprising a base, a red-sensitive layer on said base free from color-forming components, a green-sensitive layer above said red-sensitive layer, containing a nondiiusing color component for color forming development for the magenta' image, a blue-sensitive outer layer containing a non-diffusing color component'for color forming development for the yellow image, and a yellow lter interposed between the blue-sensitive and green-sensitive layers, developing the film to a black-and-white negative in a developer whose oxidation products do not couple with the color formers in the emulsion layers, rendering developable the silver halide oi' 'one of the groups of layers comprising the blue-sensitive and greensensitive layers on the one hand and Ithe redsensitive layer on the other hand and without rendering developable the silver halide of the other group, color developing the silver halide so rendered developable, rendering the previously untreated silver halide developable and color developing the same, the red-sensitive layer being color-developed in a color developer containing a cyan color component.

2. The process as denned in claim 1 in which all of the positive and negative silver is removed after the ilnal color-developing step.

A 3 3. The method of producing multicolor photographs which comprises exposing a multilayer film comprising a base, a red-sensitive layer on y said base free from color forming components,

a.greensensitive layer above said red-sensitive layer, containing a nondifiusing color compogreen-sensitive layers, developing the film to a' blaclr-and-white negative in a developer whose oxidation products do not couple with the color iormers in the emulsion layers, re-exposing the silver halide of the blue-sensitive and greensensitive layers without exposing the silver halide of the red-sensitive layer, color developing the exposed silver halide, rendering the previously unexposed silver halide in the red-sensitive layer developable, and developing the same in a color developer containing. a cyan color component.

4. The process as deilned in claim 3 wherein the red-sensitive layer is rendered developable by chemical fogging agents.

-5. The process as defined in claim 3 wherein the red-sensitive layer isrendered developable by re-exposure.

6. The process as defined in claim l wherein the red-'sensitive layer is re-expose'd with red light and the yellow-and-green-sensitive layers are re-exposed with blue-green light.

7. The process of producing multicolor photographs from a multilayer illm comprising a base,

an antihalation layer of colloidal silver on said base, a red-sensitive emulsion layer free from.

color components on said antihalation layer, a yellow -iilter layer on saidred-sensitive layer, a

-green-sensitive emulsion layer containing a nongreen-sensitive layer, and a blue-sensitive emulsion layer containing a nondiiusing color component for color forming development for the yellow image on said second yellow iilter layer, which comprises exposing said nlm to a colored object. developing the nlm to a black-and-white negative in a developer the oxidation products of which do not couple with the color components in the emulsion layers, re-exposing the redsensitive layery with white light while insuring that the anti-halation layer and the iilter layer between the green-and red-sensitive emulsion layers prevents exposure of the green-sensitive and blue-sensitive emulsion layers, color-developing the re-exposed red-sensitive emulsion layer in a color developer containing a cyan color former, rendering developable the blueand green-sensitive emulsion layers and developing the same in a color developer and submitting the film to the action of a silver-bleaching agent to remove all of the negative and positive silver 8. 'I'he process as defined in claim 1 wherein Agthe blueand green-sensitive layers are rendered developable by chemical tossing agents.

9. 'I'he process as deilned in claim 1 wherein thel blueand green-sensitive layers arerendered developable by re-exposure.

HERMAN H. DUERR.. HERBERT W. MORREALL, Ja. 

